Location systems, well known in the art, have reached a level of sophistication where accurate location coverage in buildings and other confined areas is becoming practical. Spread-spectrum and ultra-wide-band (“UWB”) technologies have offered dramatic improvements in timing accuracy, distributed systems have emerged to address coverage issues, and feasible implementations of portable inertial navigation systems (“PINS”) are emerging that can address short-term stability and coverage holes.
Use cases for in-building location systems are generally envisioned in conjunction with a pre-installed infrastructure for the location system, as well as detailed building plans allowing location information to be correlated with the layout of the building or vicinity of the incident. However, there are a number of real-world cases where this information is unavailable. Firefighters, police, and military personnel, for example, are often required to operate in environments that are uncharacterized at first contact. Databases containing building floor plans are being built up in some urban areas, but floor plans can change frequently, and many incidents occur in older and abandoned structures for which this data is unavailable. Military operations on foreign soil will often require operation in environments for which such data are unknown or intentionally withheld by an adversary.
This issue particularly affects emergency operations, such as firefighting, since lack of power, dense smoke, and other conditions can reduce visibility to inches. Characterization of the development of an incident, identification of risks such as hazardous materials, prediction of flashover and backdraft conditions, rescue operations, and planning of escape routes are all requirements that would benefit greatly from knowledge of the topology and state of the vicinity of an incident. The a priori collection of topological information, such as floor plans, is often impractical; the a priori collection of situational information, such as blocked or impassable routes, structural damage, environmental temperatures, adversary presence, presence of hazardous materials or deployment of chemical or biological weapons, is by definition impossible.
Thus, there exists a need for a method of dynamically constructing an electronic rendering of a given area that will allow a user to determine their location relative to objects or other users in the given area, as well as characteristics/attributes of the given area.